mcq 队列_MCQ | 8086微处理器中的字符串操作指令

mcq 队列

Question 1:

问题1：

A string is a collection of characters. Each Character is an of byte length which is stored at successive locations. In the 8086 microprocessor, which characters are considered in the string?

字符串是字符的集合。每个字符都有一个字节长度，存储在连续的位置。在8086微处理器中，字符串中应考虑哪些字符？

EBCDIC characters
EBCDIC字符
ASCII characters
ASCII字符
A string does not treat characters
字符串不处理字符
None of the above
以上都不是

Answer: a. ASCII characters

答： ASCII字符

Explanation:

说明：

In the 8086 microprocessor's assembly language, the String is the collection of ASCII characters.

在8086微处理器的汇编语言中，字符串是ASCII字符的集合。

Question 2:

问题2：

While performing any of the MOVE instructions over Strings, i.e. MOVSB, MOBSW or MOVSD, by default, the data is transferred from -

默认情况下，在通过字符串执行任何MOVE指令时，即MOVSB，MOBSW或MOVSD，数据将从-

DS:SI to ES:DI
从DS：SI到ES：DI
ES:DI to DS:SI
ES：DI到DS：SI
ES:SI to DS:DI
ES：SI至DS：DI
None of the above
以上都不是

Answer: a. DS:SI to ES:DI

答： 从DS：SI到ES：DI

Explanation:

说明：

By default, every move instruction transfers data from the address calculated from DS register and contents of SI to the address calculated from ES register the contents of DI, i.e. from DS: SI to ES: DI.

默认情况下，每条移动指令都将数据从DS寄存器计算出的地址和SI的内容传输到DI内容从ES寄存器计算出的地址，即从DS：SI到ES：DI。

Question 3:

问题3：

Which of the following is the correct code for repeating the MOVSB instructions 10 times?

以下哪项是将MOVSB指令重复10次的正确代码？

REPEAT MOVSB 10
重复MOVSB 10
REP 10 MOV SB
REP 10 MOV SB
CX=10
CX = 10

REP MOVSB
REP MOVSB
None of the above
以上都不是

Answer: c. CX =10 REP
MOVSB

答：c。 CX = 10代表
MOVSB

Explanation:

说明：

REP instruction repeats the given instruction(s) till CX does not becomes zero, i.e. CX != 0. So, for executing the mentioned instruction 10 times, we need to initialize the CX register with 10.

REP指令重复给定的指令，直到CX不为零，即CX！=0。因此，要执行上述指令10次，我们需要将CX寄存器初始化为10。

Question 4:

问题4：

Which of the following flags gets affected when a compare instruction, i.e. CMPSB, CMPSW or CMPSD is executed?

当执行比较指令(即CMPSB，CMPSW或CMPSD)时，以下哪个标志受影响？

Direction Flag (DF)
方向旗(DF)
Trap Flag (TF)
陷阱标志(TF)
Interrupt Flag (IF)
中断标志(IF)
Zero Flag (ZF)
零标记(ZF)

Answer: d. Zero Flag (ZF)

答案：d。 零标记(ZF)

Explanation:

说明：

Whenever a compare instruction over strings is executed, the status flags are affected. From the mentioned options, only Zero Flag is a status flag. The rest are the Control Flags.

每当执行基于字符串的比较指令时，状态标志都会受到影响。从上述选项中，只有零标志是状态标志。其余的是控制标志。

Question 5:

问题5：

At a time, on how many bits can we operate while performing any string operation?

一次，执行任何字符串操作时，我们可以操作多少位？

8 bits
8位
16 bits
16位
32 bits
32位
All of the above
上述所有的

Answer: d. All of the above

答案：d。 上述所有的

Explanation:

说明：

The string operations can be performed either on 1 byte, 2 bytes or 4 bytes at a time. In the string instructions, for example, Move instructions, in MOVSB, 'B' stands for Byte, i.e. 8 bits. Similarly, in MOVSW, 'W' stands for a word, i.e. 16 bits and in MOVSD, 'D' stands for a double word, i.e. 32 bits.

可以一次在1个字节，2个字节或4个字节上执行字符串操作。在字符串指令中，例如，MOVSB中的移动指令，“ B”代表字节，即8位。同样，在MOVSW中，“ W”代表一个字，即16位，在MOVSD中，“ D”代表一个双字，即32位。